As a display device attracting attention as a flat panel display together with a liquid crystal panel, a plasma display and the like, there is a display device using electroluminescent (hereinafter referred to as EL) elements. EL elements include an inorganic EL element in which an inorganic compound is used as an illuminant, and an organic EL element in which an organic compound is used as an illuminant. An EL element has such characteristics as high-speed responsiveness, high contrast, vibration proof and the like. The EL element may be used in high pressure or low pressure since there is no gas part inside thereof. In an organic EL element, a certain gradient can be expressed with an active matrix type drive using thin film transistors (TFT) since the driving voltage is low. However, the element is subject to humidity or the like, and the lifetime is short. On the other hand, an inorganic EL element has such characteristics as longer lifetime, a use temperature range being wide, excellent in durability and the like, comparing with the organic EL element. However, since a voltage required for emitting light is as high as 200 to 300V in an inorganic EL element, an active matrix type driving using thin film transistors (TFT) was difficult. Therefore, an inorganic EL element has been driven by passive matrix. In the passive matrix driving, there are provided a plurality of scan electrodes extending in parallel with a first direction, and a plurality of data electrodes extending in parallel with a second direction orthogonal to the first direction, and a phosphor element is interposed between the scan electrode and data electrode crossing each other. By applying an AC voltage between a pair of scan electrode and data electrode, one phosphor element is driven. In the passive matrix driving, when the number of scan lines increases, the average luminance of the whole display device is lowered. Generally, an inorganic illuminant is so configured that a luminescent material is doped in an dielectric crystal. Therefore, although luminescence is generated when UV light is irradiated, an electron is less likely to penetrate into the dielectric crystal even when an electric field is applied, and repulsion due to electrification is also strong. Therefore, a high energy electron is required to generate luminescence. In order to generate luminescence with low energy electrons, countermeasures must be taken.
According to the art described in Japanese Patent Publication No. 54-8080, a phosphor layer is so configured that ZnS forms the main body and Mn, Cr, Tb, Eu, Tm, Yb and the like are doped so as to drive inorganic EL elements (cause to emit light), whereby the luminescent brightness was improved. However, since they were only driven with a high voltage of 200 to 300V, TFTs could not be used.